Its a good start so far, your story tries to imply you have to make hard choice of who to interact with but all you get is a few different lines and then you see currently both characters changed anyway making the choice a bit pointless.
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I didn't want to sound negative, sometimes having choices that don't matter are still okay at times usually ideal in repeatable events so players can see all versions of the dialog. I think when choices should matter is when you get a hub screen to choose which character to focus on. so you could do it with how ever many characters you add have daily options to see who you give a drop of the potion to and how often you do for that character to create a diversity of character sizes based on the player's choices.